element.h

/*****************************************************************************
 * VCLib                                                                     *
 * Visual Computing Library                                                  *
 *                                                                           *
 * Copyright(C) 2021-2025                                                    *
 * Visual Computing Lab                                                      *
 * ISTI - Italian National Research Council                                  *
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 * This program is distributed in the hope that it will be useful,           *
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the              *
 * Mozilla Public License Version 2.0                                        *
 * (https://www.mozilla.org/en-US/MPL/2.0/) for more details.                *
 ****************************************************************************/
 
#ifndef VCL_MESH_VIEWS_ELEMENTS_ELEMENT_H
#define VCL_MESH_VIEWS_ELEMENTS_ELEMENT_H
 
#include <vclib/base.h>
 
#include <ranges>
 
namespace vcl::views {
 
namespace detail {
 
inline constexpr auto index = [](auto&& p) -> uint {
    if constexpr (IsPointer<decltype(p)>) {
        if (p == nullptr) [[unlikely]]
            return UINT_NULL;
        else
            return p->index();
    }
    else
        return p.index();
};
 
struct IndexView
{
    constexpr IndexView() = default;
 
    template<std::ranges::range R>
    friend constexpr auto operator|(R&& r, IndexView)
    {
        return std::forward<R>(r) | std::views::transform(index);
    }
};
 
} // namespace detail
 
inline constexpr detail::IndexView indices;
 
} // namespace vcl::views
 
#endif // VCL_MESH_VIEWS_ELEMENTS_ELEMENT_H